discrete_mathematics_with_a.../chapter_2/test_yourself.md
2026-05-28 15:46:25 -07:00

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**Test Yourself**
Page 73
1. An _and_ statement is true when, and only when, both components are _______.
**Solution**
True.
2. An _or_ statement is false when, and only when, both components are _______.
**Solution**
False.
3. Two statement forms are logically equivalent when, and only when, they always
have _______.
**Solution**
The same truth values.
4. De Morgan's laws says (1) that the negation of an _and_ statement is
logically equivalent to the _______ statement in which each component is
_______, and (2) that the negation of an _or_ statement is logically
equivalent to the _______ statement in which each component is _______.
**Solution**
or; negated; and; negated.
5. A tautology is a statement that is always _______.
**Solution**
true
6. A contradiction is a statement that is always _______.
**Solution**
false
---
**Test Yourself**
Page 86
1. An _if-then_ statement is false if, and only if, the hypothesis is _______
and the conclusion is _______.
**Solution**
true; false
2. The negation of "if $p$ then $q$" is _______.
**Solution**
$p$ and not $q$.
$$ p \wedge \neg q $$
3. The converse of "if $p$ then $q$" is _______.
**Solution**
if $q$ then $p$
$$ q \to p $$
4. The contrapositive of "if $p$ then $q$" is _______.
**Solution**
if not $q$ then not $p$.
$$ \neg q \to \neg p $$
5. The inverse of "if $p$ then $q$" is _______.
**Solution**
if not $p$ then not $q$.
$$ \neg p \to \neg q $$
6. A conditional statement and its contrapositive are _______.
**Solution**
logically equivalent.
7. A conditional statement and its converse are not _______.
**Solution**
logically equivalent.
8. "$R$ is a sufficient condition for $S$" means "if _______ then _______."
**Solution**
$R$; $S$.
9. "$R$ is a necessary condition for $S$" means "if _______ then _______."
**Solution**
$S$; $R$
10. "$R$ only if $S$" means "if _______ then _______."
**Solution**
$R$; $S$
---
**Test Yourself**
Page 99
1. For an argument to be valid means that every argument of the same form whose
premises _______ has a _______ conclusion.
are all true; true
2. For an argument to be invalid means that there is an argument of the same
form whose premises _______ and whose conclusion _______.
are all true; is false
3. For an argument to be sound means that it is _______ and its premises
_______. In this case we can be sure that its conclusion _______.
valid; are all true; is true
---
**Test Yourself**
Page 113
1. The input/output table for a digital logic circuit is a table that shows
_______.
The output signal(s) that correspond to all possible combinations of input
signals to the circuit.
2. The Boolean expression that corresponds to a digital logic circuit is
_______.
a Boolean expression that represents the input signals as variables and
indicates the successive actions of the logic gates on the input signals.
3. A recognizer is a digital logic circuit that _______.
outputs a 1 for exactly one particular combination of input signals and outputs
0s for all other combinations.
4. Two digital logic circuits are equivalent if, and only if, _______.
they have the same input/output table
5. A NAND-gate is constructed by placing a _______ gate immediately following an
_______ gate.
NOT; AND
6. A NOR-gate is constructed by placing a _______ gate immediately following an
_______ gate.
NOT; OR